TRIP13 AAA-ATPase overexpression in chromosomal instability and breast cancer

描述（由申请人提供）：非整倍性和染色体不稳定性（CIN）在实体瘤（包括乳腺癌）中非常常见。识别和表征非整倍体癌症中重复发生的遗传和表观遗传变化将对癌症预防、诊断和治疗产生巨大影响。TRIP 13被列为与CIN相关的顶级基因之一（在CIN 70标签中排名第12），并且在多个微阵列研究中，在预后不良的乳腺癌中也观察到其过表达。然而，TRIP 13的工作机制和TRIP 13过表达在乳腺癌发生中的病理学意义仍不清楚。我们的初步工作发现TRIP 13是AAA-ATP酶的成员之一，是一种新的动粒蛋白，与有丝分裂检查点沉默蛋白p31 comet直接相互作用。TRIP 13敲低延迟了中期到后期的转变，并显著降低了2D培养和软琼脂平板中的乳腺癌细胞增殖。目前的建议的目的是阐明TRIP 13的有丝分裂功能，并检查TRIP 13过表达和乳腺癌的发展之间的关系。核心假设是TRIP 13过表达促进不合时宜的有丝分裂检查点沉默，从而驱动乳腺上皮细胞中的CIN和癌症发展。三个具体目标将检验中心假设。目的1将评估TRIP 13在有丝分裂检查点中的生化功能。具体来说，我们将测试TRIP 13通过其与p31 comet的相互作用及其ATP酶活性破坏有丝分裂检查点信号传导所需的蛋白质复合物。在目标2中，我们将使用诱导型细胞系来调节TRIP 13表达水平，并确定在2D和3D细胞培养模型中对染色体稳定性和细胞增殖的影响。目的3将检查TRIP 13过表达或敲低对异种移植小鼠模型中乳腺癌细胞生长的影响。总之，拟议的工作将测试TRIP 13 ATP酶的潜在致癌功能，并评估靶向TRIP 13作为控制乳腺癌的新手段的可能性。这项工作还解决了有丝分裂检查点信号研究中的一些关键知识空白。剖析TRIP 13的功能机制是我们不断努力了解和利用乳腺癌中的非整倍体和CIN的重要一步。

DESCRIPTION (provided by applicant): Aneuploidy and chromosomal instability (CIN) are remarkably common in solid tumors including breast cancers. Identifying and characterizing recurring genetic and epigenetic changes in aneuploid cancers will have tremendous impact on cancer prevention, diagnosis and treatment. TRIP13 was ranked as one of the top genes associated with CIN (#12 in the CIN70 signature), and its overexpression was also observed in breast cancers with poor prognosis in multiple microarray studies. However, the working mechanism of TRIP13 and the pathological significance of TRIP13 overexpression in breast cancer development remain unclear. Our preliminary work found that TRIP13, a member of the AAA-ATPases, is a novel kinetochore protein and directly interacts with mitotic checkpoint silencing protein p31comet. TRIP13 knockdown delayed metaphase-to- anaphase transition and significantly reduced breast cancer cell proliferation in 2D culture and soft agar plates. The objective of current proposal is to elucidate mitotic functions of TRIP13 and examine the relationship between TRIP13 overexpression and breast cancer development. The central hypothesis is that TRIP13 overexpression promotes untimely mitotic checkpoint silencing, driving CIN and cancer development in mammary epithelial cells. Three specific aims will test the central hypothesis. Aim 1 will assess biochemical functions of TRIP13 in the mitotic checkpoint. Specifically, we will test that TRIP13, through its interaction with p31comet and its ATPase activity disrupts protein complexes required for mitotic checkpoint signaling. In Aim 2, we will use inducible cell lines to modulate TRIP13 expression level and determine the impact on chromosomal stability and cell proliferation in 2D and 3D cell culture models. Aim 3 will examine the effects of TRIP13 overexpression or knockdown on breast cancer cell growth in xenografted mouse models. Together, the proposed work will test potential oncogenic functions of TRIP13 ATPase and assess the possibility to target TRIP13 as a novel means to control breast cancers. The work also addresses some critical knowledge gaps in mitotic checkpoint signaling studies. Dissecting TRIP13 functioning mechanisms represents an important step in our continuous efforts to understand and exploit aneuploidy and CIN in breast cancers.